Interconnecting Two EFM 520S

joethemechanic · Post by **joethemechanic** » Fri. Oct. 23, 2015 11:51 pm

I have a 9,000 square foot building with offices. Right now I have a 520 running baseboard in the offices and one modine in the shop. I have 3 0ther modines I want to use for shop heat. I want to connect them to a second 520.

Here is what I'm thinking of doing. The 520s are about 100 feet apart. I would like to interconnect the systems. What would be the best way?

Post by **Rob R.** » Sat. Oct. 24, 2015 7:36 am

Do you want each boiler to be able to backup the other, or only have the existing DF520 "boost" the second one?

joethemechanic · Post by **joethemechanic** » Sat. Oct. 24, 2015 10:57 am

Rob R. wrote:Do you want each boiler to be able to backup the other, or only have the existing DF520 "boost" the second one?

Maybe not a total "backup" although I already have one run of 1 1/2" black iron going from the front boiler room to the back, When the rear boiler is in, I'll be within 20 feet with the second run of 1 1/2

joethemechanic · Post by **joethemechanic** » Sat. Oct. 24, 2015 11:13 am

Post by **Rob R.** » Sat. Oct. 24, 2015 12:08 pm

If it were me...I would just add a zone to EFM #1 and connect it to two close tees in the supply header on EFM #2. Run that zone off a thermostat, so that if the room temperature drops too far the zone turns on. This would be useful in the situation where you open a bunch of shop doors and you could use extra BTU's from EFM #1. Of course this assumes that EFM #1 has some extra capacity, and that the modines in the shop can make use of the heat.